In this work, the hot air drying of orange slices was investigated in details, such as drying time, moisture ratio, dried products' colors and some macro- and micro-elements. The study aimed to apply a computer vision system to study the color changes due to drying. The orange slices were dried at hot air drying at temperatures of 70 degrees C and 80 degrees C and explored in detail such as drying time and mass degradations. Dried products of orange slices were subjected to color analysis by image analysis system in RGB color model. Three hundred color photographs of orange fruit slices taken before and after drying were analyzed.